More often associated with poisoning and death in poorly ventilated homes with old gas ranges, a new study suggests that carbon monoxide (CO) in very small doses may protect against diabetic retinopathy (DR).
Scientists from the Medical College of Georgia (MCG) have found that HBI-002, a low-dose oral compound that ultimately delivers a small dose of carbon monoxide to the eye, appears to target key factors that damage or destroy vision in both type 1 and 2 diabetes. Currently in early-stage trials for sickle cell disease, HBI-002 can safely reduce oxidative stress and inflammation in the retina, both early and major contributors to DR, said Dr Pamela Martin from MCG’s biochemistry and molecular biology department and the Vision Discovery Institute at Augusta University. “Inflammation and oxidative stress go hand in hand. If you impact one, you generally impact the other.” At the right dose, carbon monoxide can impact both, she said.
While we tend to think of toxic fumes from cars and even death when we think of carbon monoxide, many of our own cells actively and regularly produce small amounts of the colourless, odourless gas, using the enzyme heme oxygenase 1, to protect themselves in response to increased levels of destructive states, said MCG biochemist Dr Ravirajsinh Jadeja.
“When you introduce diseases like diabetes, then these natural mechanisms fail, and we have to think of ways to enhance or re-establish those mechanisms that would normally protect us,” said Dr Martin who is now working with Dr Jadeja to further explore HBI-002’s potential. These further studies will look at the impact of the compound in both an acute ischaemic model, when the retina is suddenly deprived of oxygen because of oxidative stress, as well as a model of more natural disease progression.